REPL example:

https://blazorrepl.telerik.com/wIEiduuB379xcqGZ08

Steps to reproduce:

1. First click on the primary button. The dropdown does not open which is expected.
2. After that click on the arrow button. The dropdown does not open, but it should.

Last working version is 6.0.2:

 https://blazorrepl.telerik.com/coOiRYkB42URZx2823